CBSE Notes Class 9 Maths Chapter 7 - Introduction to Probability
These CBSE Class 9 Maths Notes Chapter 7 - "The Mathematics of Maybe: Introduction to Probability" are based on the latest CBSE syllabus and the revised NCERT textbook, Ganita Manjari. They help students understand important concepts in a simple and structured manner, making it easier to revise key topics, concepts, and examples before examinations. These notes are also useful for homework, practice, class tests, and quick revision.
The Chapter "Introduction to Probability" in the revised 2026-27 syllabus introduces students to chance and uncertainty, experiments, outcomes, events, sample space, and equally likely outcomes. It also covers probability through practical examples involving coins, dice, cards, balls, and tree diagrams, helping students understand and apply probability concepts effectively.
1.0Download CBSE Notes Class 9 Maths Chapter 7: Introduction to Probability
Download the CBSE Class 9 Maths Chapter 7 Notes PDF to understand probability through simple examples and revise important terms, concepts, and outcomes before solving questions.
2.0Important Concepts CBSE Notes Class 9 Maths Chapter 7 - The Mathematics of Maybe: Introduction to Probability
Experiment
An experiment is an action or process that gives a well-defined result. Tossing a coin, rolling a die, or drawing a card are common examples.
Random Experiment
A random experiment has more than one possible outcome, and its result cannot be predicted with certainty before it is performed.
Outcome and Trial
- Outcome: A possible result of a random experiment.
- Trial: Performing an experiment once under given conditions.
For example, getting a head or tail is an outcome when a coin is tossed.
Event
An event is a collection of one or more outcomes of a random experiment. For example, getting an even number when a die is rolled is an event.
Sample Space
The sample space is the collection of all possible outcomes of a random experiment.
For a single coin toss, the possible outcomes are head and tail. For a die, the possible outcomes are the numbers from 1 to 6.
Equally Likely Outcomes
Outcomes are equally likely when each has the same chance of occurring. A fair coin gives equal chances of getting a head or tail.
Theoretical Probability
For equally likely outcomes, theoretical probability is found by comparing the number of outcomes favourable to an event with the total number of possible outcomes.
Coin and Dice Problems
Probability questions often use coins and dice. Students may be asked to find the chance of getting a particular result, an odd or even number, a prime number, or a number within a given range. Listing all possible outcomes first makes these questions easier.
Sure and Impossible Events
- A sure event is certain to happen.
- An impossible event cannot happen.
- The probability of a sure event is 1.
- The probability of an impossible event is 0.
Complement of an Event
The complement of an event means that the event does not happen. For every event, the chances of the event and its complement together make the complete set of possible outcomes.
Probability Using Cards and Balls
Probability can also be found using playing cards, coloured balls, and numbered cards. Students need to count the total possible outcomes and then identify the outcomes that match the given event.
Tree Diagrams
A tree diagram shows possible outcomes step by step. It is useful when an experiment is performed more than once or when events happen one after another.
3.0Other Study Materials for Class 9 Maths
Students can use additional study materials along with these notes, such as:
4.0Why CBSE Notes Class 9 Maths -Introduction to Probability
These notes cover the main points of the chapter and can be used while studying and solving probability questions.
- Quick revision: Find the main points in one place.
- Easy steps: Follow the right steps when solving questions.
- Check your work: Look at the possible outcomes before giving an answer.
- Question practice: Use the notes along with textbook exercises.
- Before exams: Read the main points when you have less time.